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Conditional nonlinear optimal perturbation: Applications to stability, sensitivity, and predictability

Science China Earth Sciences 2009年第7期52卷 883-906页

作者： DUAN WanSuo mu mu State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

Conditional nonlinear optimal perturbation (CNOP) is a nonlinear generalization of linear singular vector (LSV) and features the largest nonlinear evolution at prediction time for the initial perturbations in a given constraint. It was proposed initially for predicting the limitation of predictability of weather or climate. Then CNOP has been applied to the studies of the problems related to predictability for weather and climate. In this paper, we focus on reviewing the recent advances of CNOP's applications, which involves the ones of CNOP in problems of ENSO amplitude asymmetry, block onset, and the sensitivity analysis of ecosystem and ocean's circulations, etc. Especially, CNOP has been primarily used to construct the initial perturbation fields of ensemble forecasting, and to determine the sensitive area of target observation for precipitations. These works extend CNOP's applications to investigating the nonlinear dynamical behaviors of atmospheric or oceanic systems, even a coupled system, and studying the problem of the transition between the equilibrium states. These contributions not only attack the particular physical problems, but also show the superiority of CNOP to LSV in revealing the effect of nonlinear physical processes. Consequently, CNOP represents the optimal precursors for a weather or climate event; in predictability studies, CNOP stands for the initial error that has the largest negative effect on prediction; and in sensitivity analysis, CNOP is the most unstable (sensitive) mode. In multi-equilibrium state regime, CNOP is the initial perturbation that induces the transition between equilibriums most probably. Furthermore, CNOP has been used to construct ensemble perturbation fields in ensemble forecast studies and to identify sensitive area of target observation. CNOP theory has become more and more substantial. It is expected that CNOP also serves to improve the predictability of the realistic predictions for weather and climate events play

关键词： optimal perturbation predictability stability sensitivity

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Can Adaptive Observations Improve Tropical Cyclone Intensity Forecasts?

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Advances in Atmospheric Sciences 2014年第2期31卷 252-262页

作者： QIN Xiaohao mu mu State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciences

In order to investigate whether adaptive observations can improve tropical cyclone （TC） intensity forecasts,observing system simulation experiments （OSSEs） were conducted for 20 TC cases originating in the western North Pacific during the 2010 season according to the conditional nonlinear optimal perturbation （CNOP） sensitivity,using the fifth version of the PSU/NCAR mesoscale model （MM5） and its 3DVAR assimilation system.A new intensity index was defined as the sum of the number of grid points within an allocated square centered at the corresponding forecast TC central position,that satisfy constraints associated with the Sea Level Pressure （SLP）,near-surface horizontal wind speed,and accumulated convective *** higher the index value is,the more intense the TC *** impacts of the CNOP sensitivity on the intensity forecast were then *** OSSE results showed that for 15 of the 20 cases there were improvements,with reductions of forecast errors in the range of 0.12％-8.59％,which were much less than in track *** indication,therefore,is that the CNOP sensitivity has a generally positive effect on TC intensity forecasts,but only to a certain *** conclude that factors such as the use of a coupled model,or better initialization of the TC vortex,are more important for an accurate TC intensity forecast.

关键词： adaptive observation tropical cyclone intensity forecast conditional nonlinear optimal perturbation

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Using the Lund-Potsdam-Jena Model to Understand the Different Responses of Three Woody Plants to Land Use in China

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Advances in Atmospheric Sciences 2013年第2期30卷 515-524页

作者： SUN Guodong mu mu State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 Key Laboratory of Ocean Circulation and Wave Institute of Oceanology Chinese Academy of Sciences Qingdao 266071

In this study, the approach of conditional nonlinear optimal perturbation related to initial perturbation （CNOP-I） was employed to investigate the maximum variations in plant amount for three main woody plants （a temperate broadleaved evergreen, a temperate broadleaved summergreen, and a boreal needleleaved evergreen） in China. The investigation was conducted within a certain range of land use intensity using a state-of-the-art Lund-Potsdam-Jena dynamic global vegetation model （LPJ DGVM）. CNOP-I represents a class of deforestation and can be considered a type of land use with respect to the initial perturbation. When deforestation denoted by the CNOP-I has the same intensity for all three plants, the variation in plant amount of the boreal needleleaved evergreen in northern China is greater than the variation in plant amount of both the temperate broadleaved evergreen and temperate broadleaved summergreen in southern China. As deforestation intensity increases, the plant amount variation in the three woody plant functional types carbon changes, in a nonlinear fashion. The impact of land use on plant functional types is minor because the interaction between climate condition and land use is not considered in the LPJ model. Finally, the different impacts of deforestation on net primary production of the three plant functional types were analyzed by modeling gross primary production and autotrophic respiration. Our results suggest that the CNOP-I approach is a useful tool for exploring the nonlinear and different responses of terrestrial ecosystems to land use.

关键词： conditional nonlinear optimal perturbation initial perturbation CNOP-I terrestrial ecosys-tem land use

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Ensemble of High Performance Structured Binary Convolutional LDPC Codes with Moderate Rates

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China Communications 2020年第10期17卷 195-205页

作者： Liwei mu Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials School of Physics and Telecommunication EngineeringSouth China Normal UniversityGuangzhou 510006China

An algebraic construction methodology is proposed to design binary time-invariant convolutional low-density parity-check(LDPC)*** by a proposed partial search algorithm,the polynomialform parity-check matrix of the time-invariant convolutional LDPC code is derived by combining some special codewords of an(n,2,n−1)*** achieved convolutional LDPC codes possess the characteristics of comparatively large girth and given syndrome former *** objective of our design is to enable the time-invariant convolutional LDPC codes the advantages of excellent error performance and fast *** particular,the error performance of the proposed convolutional LDPC code with small constraint length is superior to most existing convolutional LDPC codes.

关键词： algebraic construction (n,2,n−1)codes convolutional low-density parity-check(LDPC)codes fast encoding maximum achievable syndrome former memory large girth

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Differential response of injured and healthy retinas to syngeneic and allogeneic transplantation of a clonal cell line of immortalized olfactory ensheathing glia:a double-edged sword

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Neural Regeneration Research 2025年第8期20卷 2395-2407页

作者： María Norte-muñoz María Portela-Lomba Paloma Sobrado-Calvo Diana Simón Johnny Di Pierdomenico Alejandro Gallego-Ortega Mar Pérez JoséMCabrera-Maqueda Javier Sierra Manuel Vidal-Sanz María Teresa Moreno-Flores Marta Agudo-Barriuso Grupo de Investigación Oftalmología Experimental Departamento de OftalmologíaOptometríaOtorrinolaringología y Anatomía PatológicaFacultad de MedicinaUniversidad de MurciaInstituto Murciano de Investigación Biosanitaria(IMIB)Campus de Ciencias de la SaludMurciaSpain Experimental Sciences Faculty Universidad Francisco de VitoriaPozuelo de AlarcónMadridSpain Anatomy Histology and Neuroscience DepartmentMedicine FacultyUniversidad Autónoma de MadridMadridSpain Center of Neuroimmunology Service of NeurologyLaboratory of Advanced Imaging in Neuroimmunological DiseasesHospital Clínic of BarcelonaInstitut d’Investigacions Biomèdiques August Pi i Sunyer(IDIBAPS)and Universitat de BarcelonaBarcelonaSpain Medicine Faculty Universidad Francisco de VitoriaPozuelo de AlarcónMadridSpain

Olfactory ensheathing glia promote axonal regeneration in the mammalian central nervous system,including retinal ganglion cell axonal growth through the injured optic ***,it is unknown whether olfactory ensheathing glia also have neuroprotective *** ensheathing glia express brain-derived neurotrophic factor,one of the best neuroprotectants for axotomized retinal ganglion ***,we aimed to investigate the neuroprotective capacity of olfactory ensheating glia after optic nerve *** ensheathing glia cells from an established rat immortalized clonal cell line,TEG3,were intravitreally injected in intact and axotomized retinas in syngeneic and allogeneic mode with or without microglial inhibition or immunosuppressive *** and gene expression analyses were *** bulb-derived primary olfactory ensheathing glia and TEG3 express major histocompatibility complex classⅡ*** and syngenically transplanted TEG3 cells survived in the vitreous for up to 21 days,forming an *** axotomized retinas,only the allogeneic TEG3 transplant rescued retinal ganglion cells at 7 days but not at 21 *** these retinas,microglial anatomical activation was higher than after optic nerve crush *** intact retinas,both transplants activated microglial cells and caused retinal ganglion cell death at 21 days,a loss that was higher after allotransplantation,triggered by pyroptosis and partially rescued by microglial inhibition or ***,neuroprotection of axotomized retinal ganglion cells did not improve with these *** different neuroprotective properties,different toxic effects,and different responses to microglial inhibitory treatments of olfactory ensheathing glia in the retina depending on the type of transplant highlight the importance of thorough preclinical studies to explore these variables.

关键词： cell therapy immune recognition major histocompatibility complex class II(MHCII) neuroprotection olfactory ensheathing glia retinal ganglion cells

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Gas-Solid Flow,Combustion Characteristics,and Gas Emissions in a 75 t/h CFB Boiler Based on the CPFD Method

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Journal of Thermal Science 2025年第1期 323-336页

作者： HUANG Xiankun BAI Zhang ZHU Xiaoli WANG Shuoshuo mu Lin GONG Liang College of New Energy China University of Petroleum (East China) Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education School of Energy and Power EngineeringDalian University of Technology

A 3D simulation using Computational Particle Fluid Dynamics（CPFD） methods was used to calculate coal combustion in a 75 t/h industrial-scale circulating fluidized bed（CFB） *** characteristics,gas-solid flow characteristics,and gaseous pollutant emissions of CFB boilers from combustion ignition to stable operation were systematically evaluated in this *** show that the temperature distribution is relatively uniform throughout the *** the combustion process unfolds within the boiler,the gas composition curve strikingly portrays the inverse correlation between CO2and *** the combustion reaction progresses,it becomes evident that the concentration of CO2progressively increases,while the concentration of O2concurrently *** inverse relationship underscores the fundamental combustion reaction,where carbon-based fuels react with oxygen to produce carbon dioxide and release ***,a comprehensive analysis has revealed that,from ignition to stable combustion,both nitric oxide（NO） and sulfur dioxide（SO2） emissions exhibit a declining *** reduction in pollutant generation is attributed to the improvement in combustion *** complete combustion leads to lower levels of unburned hydrocarbons,which are prone to NO ***,the sulfur content in the fuel is more efficiently oxidized to sulfur trioxide（SO3） or bound in sulfates,reducing *** steady state in the simulation,the SO2mass flow rate varies significantly with the furnace height,gradually increasing from 0.07 kg·s-1at 4 m at the bottom of the furnace to a peak of 0.078 kg·s-1at 8 m in the center,and then decreasing to 0.06 kg·s-1at 20m at the top of the furnace.

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Identifying the sensitive areas in targeted observation for predicting the Kuroshio large meander path in a regional ocean model

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Acta Oceanologica Sinica 2022年第2期41卷 3-14页

作者： Xia Liu Qiang Wang mu mu School of Mathematics Zhengzhou University of AeronauticsZhengzhou 450046China Key Laboratory of Marine Hazards Forecasting of Ministry of Natural Resources Hohai UniversityNanjing 210098China College of Oceanography Hohai UniversityNanjing 210098China Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China

With the Regional Ocean Modeling System(ROMS),this paper investigates the sensitive areas in targeted observation for predicting the Kuroshio large meander(LM)path using the conditional nonlinear optimal perturbation *** identify the sensitive areas,the optimal initial errors(OIEs)featuring the largest nonlinear evolution in the LM prediction are first calculated;the resulting OIEs are localized mainly in the upper 2500 m over the LM upstream region,and their spatial structure has certain similarities with that of the optimal triggering *** on this spatial structure,the sensitive areas are successfully identified,located southeast of Kyushu in the region(29°–32°N,131°–134°E).A series of sensitivity experiments indicate that both the positions and the spatial structure of initial errors have important effects on the LM prediction,verifying the validity of the sensitive ***,the effect of targeted observation in the sensitive areas is evaluated through observing system simulation *** targeted observation is implemented in the identified sensitive areas,the prediction errors are effectively reduced,and the prediction skill of the LM event is improved *** provides scientific guidance for ocean observations related to enhancing the prediction skill of the LM event.

关键词： Kuroshio large meander targeted observation sensitive areas ROMS

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Recent Progress in Applications of the Conditional Nonlinear Optimal Perturbation Approach to Atmosphere-Ocean Sciences

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Chinese Annals of Mathematics,Series B 2022年第6期43卷 1033-1048页

作者： mu mu Kun ZHANG Qiang WANG Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China CMA-FDU Joint Laboratory of Marine Meteorology Shanghai 200438China Shanghai Frontiers Science Center of Atmosphere-Ocean Interaction Shanghai 200438China CAS Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciences and Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China Key Laboratory of Marine Hazards Forecasting Ministry of Natural ResourcesHohai UniversityNanjing 210098China College of Oceanography Hohai UniversityNanjing 210098China

The conditional nonlinear optimal perturbation(CNOP for short) approach is a powerful tool for predictability and targeted observation studies in atmosphere-ocean sciences. By fully considering nonlinearity under appropriate physical constraints, the CNOP approach can reveal the optimal perturbations of initial conditions, boundary conditions, model parameters, and model tendencies that cause the largest simulation or prediction uncertainties. This paper reviews the progress of applying the CNOP approach to atmosphere-ocean sciences during the past five years. Following an introduction of the CNOP approach, the algorithm developments for solving the CNOP are ***, recent CNOP applications, including predictability studies of some high-impact ocean-atmospheric environmental events, ensemble forecast, parameter sensitivity analysis, uncertainty estimation caused by errors of model tendency or boundary condition, are reviewed. Finally, a summary and discussion on future applications and challenges of the CNOP approach are presented.

关键词： Conditional nonlinear optimal perturbation Atmosphere Ocean Targeted observation Predictability

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Impacts of parameter uncertainties on deep chlorophyll maximum simulation revealed by the CNOP-P approach

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Journal of Oceanology and Limnology 2020年第5期38卷 1382-1393页

作者： GAO Yongli mu mu ZHANG Kun Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China College of Science China University of Petroleum(East China)Qingdao 266580China Institute of Atmospheric Sciences Fudan UniversityShanghai 200433China Qingdao National Laboratory for Marine Science and Technology Qingdao 266237China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

Parameter uncertainty is a primary source of uncertainty in ocean ecosystem *** deep chlorophyll maximum(DCM)is a ubiquitous ecological phenomenon in the *** a theoretical nutrients-phytoplankton model and the conditional nonlinear optimal perturbation approach related to parameters,we investigated the eff ects of parameter uncertainties on DCM ***,the sensitivity of single parameter was *** sensitivity ranking of 10 parameters was obtained by analyzing the top four specifi *** most sensitive parameter(background turbidity)aff ects the light supply for DCM formation,whereas the other three parameters(nutrient content of phytoplankton,nutrient recycling coeffi cient,and vertical turbulent diff usivity)control nutrient *** explore the interactions among diff erent parameters,the sensitivity of multiple parameters was further studied by examining combinations of four *** results show that background turbidity is replaced by the phytoplankton loss rate in the optimal parameter *** addition,we found that interactions among these parameters are responsible for such diff ***,we found that reducing the uncertainties of sensitive parameters could improve DCM simulations *** with the sensitive parameters identifi ed in the single parameter analysis,reducing parameter uncertainties in the optimal combination produced better model *** study shows the importance of nonlinear interactions among various parameters in identifying sensitive *** the future,the conditional nonlinear optimal perturbation approach related to parameters,especially optimal parameter combinations,is expected to greatly improve DCM simulations in complex ecosystem models.

关键词： deep chlorophyll maximum(DCM)simulation parameter uncertainty conditional nonlinear optimal perturbation related to parameters(CNOP-P) sensitivity

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Behaviour of cranes(family Gruidae)mirrors their phylogenetic relationships

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Avian Research 2021年第3期12卷 285-295页

作者： Nela Nováková Jan Robovský Faculty of Science University of South BohemiaBranišovská176037005ČeskéBudějoviceCzechia

Background:The behavioural repertoire of every species evolved over time and its evolution can be traced through the phylogenetic relationships in distinct ***(family Gruidae)represent a small,old,monophyletic group with well-corroborated phylogenetic relationships on the species level,and at the same time they exhibit a complex and well-described behavioural ***:We therefore investigated the evolution of behavioural traits of cranes in a phylogenetic context using several phylogenetic approaches and two types of trait *** cranes exhibit more than a hundred behavioural displays,almost one third of which may be phylogenetically ***:More than half of the analysed traits carry a significant phylogenetic *** ancestor of cranes already exhibited a quite complex behavioural repertoire,which remained unchanged in Balearicinae but altered greatly in Gruinae,specifically by the shedding of traits rather than their *** scoring has an influence on results within the Gruinae,primarily in genera Bugeranus and ***:Albeit the behavioural traits alone cannot be used for resolving species-level relationships within the Gruidae,when optimized on molecular tree,they can help us to detect interesting evolutionary transformations of behaviour repertoire within *** Limpkin(Aramus guarauna)seems to be the most enigmatic species and should be studied in detail for its behavioural repertoire,which may include some precursors of crane behavioural traits.

关键词： Ancestral behavioural repertoire Evolution Phylogenetic signal

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